The entire genome must be replicated precisely, once for every cell division.

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#Id: 1014

#Unit 5. Developmental Biology

A fruit fly’s sex is determined predominantly by the number of X chromosomes in each cell.

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#Id: 1015

#Unit 5. Developmental Biology

A fly have two X chromosomes and three sets of autosomes, it is a mosaic.

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#Id: 1016

#Unit 5. Developmental Biology

In Drosophila, the X chromosome contains genes encoding four transcription factors that activate the critical gene in Drosophila sex determination, the X-linked locus Sex-lethal (Sxl).

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#Id: 1017

#Unit 5. Developmental Biology

Three major RNA targets to which the female-specific Sxl transcript binds: 

Pre-mRNA of Sxl itself

msl2 gene

pre-mRNA of transformer (tra)

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#Id: 1018

#Unit 5. Developmental Biology

The Drosophila doublesex (dsx) gene is active in both males and females, but its primary transcript is processed in a sex-specific manner.

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#Id: 1019

#Unit 5. Developmental Biology

The processes by which the three ectodermal regions are made physically and functionally distinct from one another is called neurulation.